1. Field of the Invention
This invention relates generally to the water circulation system of a swimming pool and is more particularly directed to a flow control device for use in a surface skimmer incorporated in the gutter disposed around the perimemter of the pool.
2. Description of the Prior Art
There are generally two methods used to remove dirt, debris and other foreign matter from the surface of the water in a swimming pool. One method is to provide surface skimmers spaced along the periphery of the pool wall. Each surface skimmer includes an opening in the pool wall, generally at the height of the normal level of the water in the pool, connected to the circulation system of the pool which may include conduits leading to a filter and a pump to recirculate the water. The inlet of the opening is generally provided with a weir to control the flow of water through the skimmer. The weir is installed such that when the circulation system is operating to produce skimming, it is deflected inwardly from the inlet opening to permit the rapid flow of the surface layer of water over the top edge of the weir, and to close the opening when skimming is stopped. When the weir is in its closed position, it serves as a barrier against a return to the pool of debris within the skimmer conduit. The weirs are generally buoyant structures mounted to permit deflection about a lower edge, and examples of such weirs may be found in U.S. Pat. Nos. 3,555,574, 3,716,873, 3,815,161 and 3,939,505.
Another method for removing foreign matter from the surface of the pool water is to provide a continuous gutter around the periphery of the pool in which water continually flows over the top of the gutter wall into a lower-level gutter trough. Such gutter designs are exemplified in U.S. Pat. Nos. 1,797,397 and 2,932,397. While such gutter designs provide sufficient skimming under normal flow conditions, heavy surges or waves produced by large number of swimmers or high level of activity within the pool increases the flow of water over the gutter and tends to flood the gutter, stopping any skimming action until the water is drained and often washing the dirt already in the gutter back into the pool.
Attempts have been made to resolve these and other difficulties associated with the perimeter gutter design, and to combine the advantages of the suface skimmer design with the perimeter gutter design. Examples may be found in U.S. Pat. Nos. 3,319,264, 3,363,767, 3,155,989, 3,668,713, 3,668,714, 4,112,526, 4,121,307 and 4,146,937. In the patent to Scarano (3,319,264), a trough extending around the perimeter of the swimming pool is provided with openings through which the water spilling over the lip of the wall flows through an enclosed passage to the water filter. In one embodiment, hinged flaps close the openings of the trough to prevent back flow of water if the level of the water within the passage exceeds the height of the openings.
The other patents incorporate weir skimmers in the wall of the gutter facing the pool. Ellis (U.S. Pat. No. 3,362,767) provides a manually-controlled flap gate to close the opening to the weir. In the patent to Anderson (U.S. Pat. No. 3,155,989), a gate made of a buoyant material is hinged at its lower edge to control the flow of water through the skimmer. The opening of the gate is dependent upon the quantity of water in the gutter which, in turn, is controlled by the positioning of baffle plates across the width of the gutter. In the Patterson U.S. Pat. Nos. 4,112,526 and 4,121,307, the flow of water through the skimmer openings are controlled by float-actuated closures which respond to the level of the water in the gutter to shut off flow through the skimmer openings. In the patents to Baker (U.S. Pat. Nos. 3,668,713 and 3,668,714), hinged, counter-weighted control plates respond to the level of the water in the pool to shut off flow through the weir opening.
The flow control devices utilized in the surface skimmers of the prior art exhibit problems. The devices which utilize floats can hang up due to debris getting caught between the float and the sidewalls of the skimmer housing, thus allowing water to continually spill pass. Flow control devices which incorporate spring-biased movable plates are subject to being jammed in either the open or close position. Plates which incorporate weights for counterbalance require adjustment of the weights for proper operation. Similarly, weighted butterfly-type plates disposed at the water line tend to chatter and otherwise create disturbing noises under the action of waves when they open and close.